So the user will simply look for the product and click on the Add To CartÂ button. In the web application, you will have a nice looking HTML page with Javascript support. It simply maintains the list of items which are added to the cart by the user. The sole purpose of cartItemslist is to store the purchased item in the cart or remove the item from the cart.

It also maintains a cartItemslist with a type Product, similar to the products list in products class. It provides all the required operations a cart should have such as: This is a concrete class which act as a virtual cart to store the items temporarily. If you have read my previous article on Understanding Collections in JAVA then you will be familiar with the Generic Collection.Īs we have provided the Product class inside the braces as new ArrayList(), this will tell the compiler that the list is of type Product and it can only contain an item which belongs to type Product. For simplicity, I’m using Products class to initialize objects.Īs you can see, the initStoreItems()methodÂ is used to add the products into a new ArrayListÂ of typeÂ Product. In real-world application, the items will be retrieved from user session or database. In other words, this class is used to initialize your store as soon as the application is started. The role of this class in your Shopping Cart Application is to provide you with the store products. Why do I need to Override equals and hashCode method in Java?.Therefore, it is very important to override hascode() and equals() method of an object.įollowing is a very well explained answer that tells you the importance of overriding hashcode and equals for object comparison.

If both (hash code & properties value) are same then the object is considered equal otherwise not equal. Their hash code and properties are compared.

hashCode()is a unique hash/number attached to every object whenever the object is created.

equals()method is used to compare two objects based on their properties.

I have also override the Hash and Equals method. This is a concrete class which contains Product properties and provides setters and getters for it. I will take each class one by one and explain the significance of it.

For simplicity, all of the code will reside inside this package.įor this example project, make sure all of the above-mentioned classes resides under the same package, i.e, collections.shoppingcart.Create the following package under your src folder,.Create a new Java Project with whatever name you like.

Online grocery shopping project in java